Exon 3-deleted and full-length growth hormone receptor polymorphism frequencies in an Iranian population

The functional role of the exon 3 growth hormone receptor (d3GHR) polymorphism in human and its distributions in different populations is not clearly understood. The presence of full length growth hormone (flGHR) is the most important in metabolic risk factors. The aim of this study was to define the frequency distribution of d3GHR/full-length GHR in an Iranian population. The presence of the d3GHR polymorphism in healthy volunteers blood DNA (n=80, male=30 and female=50) was assessed by PCR using specific primers. The 935-bp and 592-bp fragments indicate the presence of the flGHR and the exon3 deletion of GHR, respectively. The distribution of the GHR genotypes in this study were 31.4% (n=24) for fl/flGHR, 49.7 % (n=41) for fl/d3GHR, and 19.0 % (n=15) for d3/d3GHR. Frequencies of fl allele and d3 allele were 55.4% and 44.4% within whole population, respectively. There was no difference in allels frequencies of GHR in male (fl=0.583, d3=0.417) and female (fl=0.540, d3=0.460) when compared with whole population. The results showed that the frequency of d3/d3GHR isoform was significantly lower than that of the fl/flGHR and d3/flGHR. The frequencies of GHR polymorphisms were likely consistent with previous reports. Our finding is also consistant with Mexican population. The advantage of existence of the d3/d3 rather than fl/flGHR polymorphisms in individuals and in correlation with diseases opens new insights for GH and insilin-like-growth factor-1 (IGF-I) axis.